Dental implants are commonly used in today's dental practices to support various prostheses. Challenges to the successful placement of dental implants include poor bone quality and various hidden anatomical features such as nerves, roots, and sinus cavities. Surgical preplanning methods and drill guide apparatuses may be used to better address these challenges. With edentulous cases, surgical drill guide apparatuses can be divided into two categories: bone borne surgical drill guides and gum tissue borne surgical guides.
Bone borne surgical drill guides are made to fit on a patient's jawbone, and can be made from either a digital jawbone model or rapid-prototyped physical jawbone model of the patient. The primary problem with bone borne surgical guides is the invasiveness of the amount of flapping of the gum tissue that the surgeon has to create in order for the guide to fit correctly on the patient jawbone. The amount of flapping required increases the likelihood of surgical risks and complications, including blood loss, infection, healing problems, and overall pain experienced by the patient. Flapping and suturing also requires a great deal of surgical time. In addition to the problems associated with the surgical procedure, difficulties may also arise when the jawbone has low density, which happens often with Maxilla bones in posterior region. Low bone density makes it difficult to define the contour of the bone in CT images, which may cause the bone borne surgical drill guide to fit poorly. Thus, the use of bone borne surgical drill guides has drawbacks and it would be preferred to overcome their associated problems.
Gum tissue borne surgical drill guides are made to fit on top of a patient's gum tissue without the need for any surgical incisions to stabilize the guide. In order to create this type of surgical guide, the surface scan data of the gum tissue and the tomography data of the jawbone need to be accurately aligned and mapped. For this purpose, usually an imaging template is worn by the patient during tomography scanning, and the fiducial markers on the device are used for alignment of the different data sets. While this method is less surgically invasive than the bone borne method, gum tissue borne surgical guides lack stability. Gum tissue is in a constant state of movement and drift, and is also pliable with pressure. Moreover, certain health conditions and even the intake of certain foods make gum tissue more prone to swelling. These conditions may prevent the accurate positioning of the device in the mouth. Here, even if the surgeon uses anchor screws, they may be securing the device in the wrong position. This type of surgical drill guide sacrifices accuracy for convenience. Thus, it would be preferred to overcome these problems.
Accordingly, it would be desirable to provide a stable and accurate surgical drill guide apparatus that requires only minimum flapping and fits to both gum tissue and one or multiple small areas of jawbone. Such apparatus may increase the stability of the surgical guide by clasping and/or contacting the jawbone, while improving the overall fit and minimizing the need of flapping by also clasping and/or contacting selected areas of the gum tissue at the same time. The apparatus may be configured to accurately place dental implants according to the planned positions.
It would also be preferable to provide an apparatus that may be custom designed to suit the unique anatomical features of each individual. The device may be designed on a digital anatomical jawbone model with accurately mapped and aligned gum tissue information, and may be rapid prototyped or milled as a drill guide frame or frame set. Also, the apparatus may be made by hand on the rapid prototyped or CNC milled physical anatomical model that partially exposes the jawbone structure.